This invention relates to a system for monitoring a sample during centrifugation and, more particularly, to a system for monitoring the fluid volumes collected as a function of time during the centrifugation of a sample of core material that has been removed from the borehole of an oil well.
The use of a centrifuge to measure properties, such as relative permeabilties and capillary pressures, of core material is well known to prior art workers in the petrophysical measurements of core material. In general, a fluid saturated core sample is rotated, and the fluids that are displaced from the sample are collected in an attached collection tube. The most difficult aspect of the measurement is monitoring the fluid volumes as a function of time; these measurements are generally performed by a technician who observes and records the fluid levels at predetermined intervals. However, since test runs may take several days and fluid changes may occur very rapidly during the first portion of the test, the prior art method of manually monitoring the process is tedious and may result in poor accuracy. In addition, the prior art has monitored the fluid production by programming a camera to take pictures at preset times. Again, this process is a tedious one, since the developed film must be analyzed manually to gather the appropriate data. Another drawback of this method is that if a malfunction occurs during the run, which can last up to a week, the malfunction often is not detected until the film has been developed; hence, corrective action is usually impossible. Moreoever, the number of data points that can be collected by this method is limited to the number of exposures available on the film.
Therefore, it is an object of the present invention to provide a system that automatically monitors a sample during centrifugation and provides a plurality of data points indicative of the characteristic of such sample that is being tested by the centrifugation.